Invasive exotic plant monitoring in Black Canyon of the Gunnison National Park and Curecanti National Recreation Area, 2003–2015

Perkins, Dustin; Wight, Anneth

Invasive exotic plant (IEP) species are a significant threat to natural ecosystem integrity and biodiversity, and controlling them is a high priority for the National Park Service. The Northern Colorado Plateau Network (NCPN) selected the early detection of IEPs as one of 11 monitoring protocols to be implemented as part of its long-term monitoring program. This report documents and maps invasive plant patches detected at Black Canyon of the Gunnison National Park (NP) and Curecanti National Recreation Area (NRA) during 2014–2015. It also summarizes all work completed at the parks from 2010 to 2015 (representing two full rotations of desired monitoring routes) and presents data collected by Utah State University in 2003 and 2004. From 2014 to 2015, a total of 280 kilometers were monitored at Black Canyon of the Gunnison NP and Curecanti NRA. A total of 3,788 patches of 19 priority IEP species were detected on monitoring routes and transects in 2014–2015. Canada thistle (Breea arvensis), common mullein (Verbascum thapsus), yellow sweetclover (Melilotus officinale), musk thistle (Carduus nutans), reed canarygrass (Phalaroides arundinacea), and Russian thistle (Salsola sp.) were the most commonly detected priority IEPs over both parks. In Black Canyon of the Gunnison NP, the most commonly detected species were yellow sweetclover, musk thistle, common mullein, reed canarygrass, and Canada thistle. Red Rock Canyon, the Gunnison River, shoreline of Blue Mesa Reservoir, and the Black Canyon Road had the most invasive plants per kilometer. The highest percent cover of total invasive species in 2014–2015 was 18.3%, in the Cooper/Neversink area. Other high percent covers occurred along the Red Rock Canyon (8.8%), Gunnison River (7.1%), Northern Roads (2.9%), and Southern Roads (1.2%) monitoring routes. Total invasive plant cover was <1.0% in other areas in 2015. Patches of common burdock (Arctium minus), musk thistle, and Canada thistle all declined in Red Rock Canyon compared to the two earlier time periods and common mullein has remained low, which has resulted in an overall decrease in the number of patches. Along the Gunnison River, common burdock, Canada thistle, reed canarygrass, and common mullein all declined from the earlier sampling periods. Along the East Portal Road, Canada thistle and musk thistle have declined, resulting in an overall decrease in the number of IEP patches. The number of IEP patches increased dramatically along the shores of Blue Mesa. Canada thistle, perennial pepperweed (Cardaria latifolia), musk thistle, bull thistle (Cirsium vulgare), scentless chamomile (Matricaria perforata), reed canarygrass, Russian thistle, and common mullein all had large increases. In the Elk Creek Management Area, overall patch numbers went down, with the largest decreases seen in kochia (Bassia sieversiana) and Russian thistle, while Canada thistle increased. Network staff will return to Black Canyon of the Gunnison NP and Curecanti NRA in 2017 to begin the third rotation of monitoring.

Invasive exotic plant monitoring in Black Canyon of the Gunnison National Park and Curecanti National Recreation Area, 2003–2015

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